Newton's First Law of Motion
Car on Level Track
A car maintains constant motion on a level air track.
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- Air track
- Air track car
A car on a level air track is shown to move at constant speed, including the special case of remaining at rest.
Car on Inclined Track
Air track simulation of Galileo's rolling ball experiment.
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- Air track
- Air track car
- Wooden wedge
- Meter stick
A series of experiments is done with varying air track inclinations and with the car being released from one end of the track with the same initial speed each time. The horizontal distance reached is observed to change with inclination, but the car always stops at the same vertical height. At zero inclination, the car would have to travel an infinite distance to reach this same height. Therefore, it will maintain its motion with a constant speed.
Ball Dropped
A ball is dropped while walking or running.
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- A small ball
- A container (box) to receive the ball
A ball which is dropped by a person while walking or running is shown to maintain its horizontal speed. In order to hit its target (a box on the floor), it must be released before the runner reaches the target.